You've been annoyed by them in restaurants, stores, and trains. But did you ever stop to think that those non-stop cell phone talkers might be giving away sensitive information about your business?

In a study completed earlier this year, European mobile services carrier Vodafone found that more than 70 percent of all workers talk business on their mobile phones in public, with one in five talking about business-critical subjects, such as sales leads. Fifteen percent admit to openly discussing confidential new products or services while traveling.

Think no one ever really pays attention to those calls? Think again. In its study of more than 2,000 mobile phone users, Vodaphone discovered that more than a quarter of workers have actually followed up on a lead they have overheard in someone else's phone conversation.

"This research shows that people need to consider which contact method they use when communicating sensitive information on the move -- whether it's voice, text or email," says Mark Bond, director of enterprise business at Vodafone UK. In public places, users should switch to more discrete modes, such as text or mobile email, he said.

More than half of the mobile phone users surveyed say they always talk business on the phone in public, and never switch to a more private communication channel, such as email or text. Only 6 percent of people use code names for people, places, or projects when talking in public.

And it's not just company security that's in jeopardy, Vodafone said. The research also shows that mobile phone users admit to discussing their love lives, and even sex lives -- as well as those of other people -- while talking on the phone in public. While only one in five discusses their own love lives - health, careers, and children are more popular conversation topics -- six out of ten are quite happy to discuss the private lives of their friends.

Vodafone revealed the survey data as part of the unveiling of a new service that improves reception on trains, hopefully reducing the number of times that passengers will have to hear someone shout, "Can you hear me now?" on their next trip through the English countryside.

— Tim Wilson, Site Editor, Dark Reading